<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>p10浮动综合practice4</title>
    <style>
        * {
            padding: 0;
            margin: 0;
        }

        .box1 {
            height: 50px;
            background-color: gray;
            margin-bottom: 10px;
        }

        .box2 {
            width: 990px;
            height: 100px;
            background-color: gray;
            margin: 0 auto;
            margin-bottom: 10px;
        }

        li {
            list-style-type: none;
        }

        .box3 {
            width: 990px;
            height: 80px;
            /* background-color: skyblue; */
            margin: 0 auto;
            margin-bottom: 10px;
        }

        .box3 li {
            float: left;
            width: 240px;
            height: 80px;
            background-color: gray;
            margin-right: 10px;

        }

        .box3 .last3 {
            margin-right: 0;
        }
        .box4 {
            width: 990px;
            height: 150px;
            margin: 0 auto;
            margin-bottom: 10px;
            /* background-color: skyblue; */
        }
        .box4 li {
            float: left;
            width: 240px;
            height: 150px;
            background-color: gray;
            margin-right: 10px;
            margin-bottom: 10px;
        }
        .box4 .last4 {
           
            margin-right: 0;
        }
        .box5 {
            height: 100px;
            background-color: gray;
        }
    </style>
</head>

<body>
    <div class="box1"></div>
    <div class="box2"></div>
    <div class="box3">
        <ul>
            <li></li>
            <li></li>
            <li></li>
            <li class="last3"></li>
        </ul>
    </div>
    <div class="box4">
        <ul>
            <li></li>
            <li></li>
            <li></li>
            <li class="last4"></li>
        </ul>
    </div>
    <div class="box5"></div>
</body>

</html>